Electric toothbrushes including electric sonic wave toothbrushes known heretofore include a bass brushing tooth brush places the brush in the part between the tooth and the gum at an angle (at an angle of approximately 45 degrees) and vibrates the brush to the right and left in back-and-forth linear motion, a rolling brushing toothbrush that rotates back and forth (forward and backward) over a predetermined angle range around a shaft and moves from the gum to the tooth rotating, and so on.
The drive of toothbrushes like these involves many structures for converting the rotation of a rotating DC motor that rotates regularly around a shaft into back-and-forth linear motion or back-and-forth rotating motion, via a motion direction converting mechanism. Furthermore, besides these structures, a structure to move a toothbrush in back-and-forth linear motion by means of a linear drive actuator, and a structure to move a toothbrush in back-and-forth rotating motion by making a resonance vibrating mechanism apart from the drive source resonate by the vibration of an actuator, are known.
With an electric toothbrush structured to move the brush part in back-and-forth linear motion by means of a linear drive actuator, as shown in patent literature 1, the linear actuator directly produces back-and-forth vibration in the axial direction of an output shaft that is directly connected with the brush part, and makes possible bass brushing. With this structure, there is little power loss due to a motion converting mechanism, and makes possible fast vibration.
Furthermore, with an electric toothbrush of a structure having an actuator and resonance vibrating mechanism apart from the drive source, as shown in patent literature 2, a drive means with an electro magnet and permanent magnet vibrates the resonance vibrating mechanism having a lever arm. By this means, the lever arm that is coaxially connected with the brush part moves in swinging motion, making possible rolling brushing.